Vent openings are typically provided in roof soffits for venting air out of a building's attic space and/or for providing a fluid pathway through which air may enter the attic space from the outside environment. Other vent openings may be provided for venting pressurized air or other fluid from inside the building to the exterior, such as from a laundry dryer or an HVAC unit, in which vented air is routed through a conduit. Such vent openings are typically covered by a fixed grill with slots and louvers that continuously permit airflow between the outside environment and the building's attic, while preventing birds and other small animals from entering the building through the soffit vent cover. However, fixed grills are always open, and can permit small insects and the like to access the building's interior.